The invention relates generally to semiconductor devices, and more particularly, to a system and method for creating three-dimensional semiconductor devices.
In U.S. Pat. No. 5,955,776, which is hereby incorporated by reference, a method and apparatus for manufacturing spherical-shaped semiconductor integrated circuit devices is disclosed. Although certain systems and methods for performing various processing operations are discussed in the above-referenced patent, it is desired to further improve on the operations. For example, in making a p-n junction diode, a first type (e.g. n-type) outer layer is diffused onto a second type (e.g., p-type) spherical shaped semiconductor substrate. It is desired that both the outer layer and the inner substrate are maintained at an appropriate shape, thickness, and diffusion concentration.
In U.S. patent Ser. No. 09/490,650, now U.S. Pat. No. 6,365,493, and Ser. No. 09/489,782, now U.S. Pat. No. 6,331,477 which are hereby incorporated by reference, methods for doping material on a spherical shaped substrate in a non-contact environment are disclosed. These methods can be used to make spherical p-n junction diodes for solar cell applications. It is desired, however, to make uniform sized spherical p-n diodes in a continuous operation (e.g., a single step).
In U.S. patent Ser. No. 09/363,420, now U.S. Pat. No. 6,264,742, and Ser. No. 09/672,566, now U.S. Pat. No. 6,383,287, which are hereby incorporated by reference, methods for making single crystal devices and for making uniformly thick p-n junctions on these devices are disclosed, respectively. It is desired, however, to better automate the production of these devices in a highly manufacturable setting.
A technical advance is achieved by a new and improved jet system for making spherical shaped devices. In one embodiment, the system includes a supply system for providing predetermined amounts of raw material at a temperature at or above a melting point of the material, and for moving the predetermined amounts of melted raw material without physical contact so that a liquid surface tension of each predetermined amount of melted raw material will cause the material to form into a spherical shape device. The system also includes a container of powder in which the solidified spherical shaped devices are received from the supply system and means for separating the powder from the solidified spherical shaped devices after the devices have been received.
In another embodiment, the system includes a supply system for providing predetermined amounts of raw material into a chamber, which is used for melting the raw material. The melted raw material is then provided to a dropper for measuring predetermined amounts of the melted raw material (droplets) and releasing the droplets into a drop tube, where they are cooled and solidified into spherical shaped silicon devices. The system includes a container of silicon powder in which the solidified spherical shaped devices are received from the drop tube, the container including a stirring mechanism for agitating the silicon powder. The system also includes a separating device for separating the powder from the solidified spherical shaped devices after the devices have been received into the container.